This invention relates to diagnostic ultrasound systems, and more particularly, to displays for diagnostic ultrasound systems.
Diagnostic ultrasound systems are commonly used to image a wide variety of organs and tissues within the human body. A typical diagnostic ultrasound imaging system 10 is shown in FIG. 1. The diagnostic ultrasound imaging system 10 includes an ultrasound transducer 14 that is adapted to be placed in contact with a portion of a body that is to be imaged. The transducer 14 is coupled to a system chassis 16 by a cable 18. The system chassis 16, which is mounted on a cart 20, includes a keyboard 24 by which data may be entered into a processor (not shown) that is included in the system chassis 16. A display monitor 30 having a viewing screen 34 is placed on an upper surface of the system chassis 16. As is typical, the viewing screen 34 has the same 4:3 aspect ratio as conventional television and computer monitors.
While displays having a 4:3 aspect ratio are suitable for performing many imaging tasks, they are far from ideal for many imaging applications. One example of an imaging application that is not well suited for display on a monitor having a 4:3 aspect ratio is a panoramic image. In panoramic imaging, the transducer 14 is scanned along the surface of a portion of the body, such as an arm. FIG. 2 shows a panoramic image 40 of an arm displayed on the viewing screen 34 of an ultrasound imaging system. Because panoramic images are created by scanning the transducer 14 along a path, panoramic images are typically horizontally elongated, as is the panoramic image 40 shown in FIG. 2. As shown in FIG. 2, most of the screen 32 is blank, and the anatomical features in the image 40 are quite small. Furthermore, the number of pixels used to display the image, and hence its resolution, may be significantly limited. The anatomical features could be shown in greater detail and with greater resolution by increasing the scale of the image 40, but doing so would cause the end portion of the image 40 to be outside the viewing area of the screen 32. The problem with displaying panoramic images using conventional display monitors is, therefore, not only the size of the anatomical details in the image, but also the resolution at which those details may be displayed. Thus, conventional display monitors, such as those having an aspect ratio of 4:3, do not provide optimum results for panoramic imaging.
Another imaging application that produces an image having an aspect ratio similar to panoramic imaging is shallow depth scanning, which is also known as peripheral scanning. The scan depth of such images is often very shallow so that the horizontal dimension of the image is significantly greater than the vertical dimension. As with panoramic images, it can be difficult to see fine detail in images produced by peripheral scanning without increasing the scale of the image. However, increasing the scale of the image may cut off a portion of the image. It is therefore not possible to see the entire image and still display the image with enough resolution and size to make it possible to clearly view fine anatomical features.
Another example where conventional display monitors used in ultrasound imaging systems provide limited performance is in the side-by-side presentation of multiple images. With reference to FIG. 3, in side-by-side imaging, the viewing screen 34 is divided into two areas, and an image is displayed on each area of the screen 34. Since the viewing screen has an aspect ratio of 4:3, each of the areas on which an image is displayed has an aspect ratio of 2:3. As shown in FIG. 3, an ultrasound image 50 is displayed on the left hand side of the viewing screen 34, and text or a second image 52 is displayed on the right hand side of the screen. The image 52 may be, for example, another ultrasound image or a magnetic resonance image, an x-ray, a nuclear image, an image obtained by CT scanning, or a graphical image, to name a few examples. The display of the ultrasound image 50 with an aspect ratio of 2:3 only serves to exacerbate the problems described above with displaying certain types of ultrasound images.
Another application of ultrasound imaging that provides less than optimum performance because of the limitations of conventional display monitors is spectral Doppler scanning. In spectral Doppler scanning, a portion of the viewing screen 34 is used to display a two-dimensional ultrasound image that generally includes a blood vessel. Another portion of the viewing screen 34 is used to display a graph in which the velocity of blood in the vessel being scanned is displayed on the xe2x80x9cYxe2x80x9d axis as a function of time, which is displayed along the xe2x80x9cXxe2x80x9d axis in scrolling fashion. A typical example of the viewing screen 34 when the ultrasound imaging system 10 is being used for Doppler scanning is shown in FIG. 4. As shown in FIG. 4, an ultrasound image 60 is typically displayed on the upper portion of the viewing screen 34 and a velocity graph 62 is displayed on the lower portion of the viewing screen 34. Although the wider aspect ratio of the ultrasound image 60 can be advantageous for reasons discussed herein, the presence of the velocity graph 62 prevents the full height of the viewing screen 34 from being used to display the ultrasound image 60. It would be preferable to be able to display the ultrasound image 60 using the full height of the viewing screen 34 and still be able to display the velocity graph 62.
Still another example of an imaging application for which conventional display monitors are not well suited for display is deep imaging. In deep imaging, a relatively narrow image is obtained fairly deep into the body. An example of an image 70 obtained by deep imaging is shown in FIG. 5. The problem of displaying the deep image 70 using the viewing screen 34 having a 4:3 aspect ratio is similar to, but the reverse of, the problem of displaying relatively wide images using the viewing screen 34. More specifically, since the image 70 is substantially taller than it is wide, a substantial portion of the viewing screen 34 is unused. Furthermore, it may be difficult to see fine anatomical details in the image 70. These details can be displayed with greater resolution (i.e., using more pixels) and with a larger size by increasing the scale of the image 70, but doing so would cut off the upper and lower ends of the image 70. Thus, viewing screens 34 used with conventional ultrasound imaging systems are less than optimum for displaying both relatively wide images and relatively narrow images. In both cases, substantial areas of the viewing screen 34 are unused, thus reducing the number of pixels of the screen 34 used to display the image.
It would be desirable to make the screen 34 wider. However, given the 4:3 aspect ratio of the screen 34, doing so would proportionately increase the height of the screen 34, thus also making it necessary for the height of the monitor 30 to be increased. Yet, increasing the height of the monitor 30 would make the imaging system quite bulky and eliminate the desirable low-profile appearance of the system 10.
An ultrasound imaging system for optimally viewing ultrasound images includes a system chassis, an ultrasound transducer coupled to the system chassis, and a display monitor coupled to the system chassis. The display monitor has a viewing screen with an aspect ratio that is substantially greater than 4:3, such as an aspect ratio of 16:9. As a result, certain types of images having a wide aspect ratio, such as panoramic or peripheral images, can be shown with greater size and resolution without cutting off end portions of the image. Furthermore, side-by-side ultrasound images can more optimally be displayed, and Doppler scanned images can be displayed as side-by-side images. The display monitor is preferably mounted on a rotatable base. If the image is wider than it is tall, the display monitor may be rotated to a position in which the aspect ratio of the viewing screen is substantially greater than 4:3. If the image is taller than it is wide, the display monitor may be rotated to a position in which the aspect ratio of the viewing screen is substantially less than 3:4. The display monitor is preferably mounted on top of the system chassis, and the system chassis is preferably placed on a wheeled cart.